WBJEE · Physics · Ray Optics
Two identical equiconvex lenses, each of focal length \(f\) are placed side by side in contact with each other with a layer of water in between them as shown in the figure. If refractive index of the material of the lenses is greater than that of water, how the combined focal length \(F\) is related to \(f ?\)
- A \(F>f\)
- B \(\frac{f}{2} < F < f\)
- C \(F < \frac{f}{2}\)
- D \(F=f\)
Answer & Solution
Correct Answer
(B) \(\frac{f}{2} < F < f\)
Step-by-step Solution
Detailed explanation
The given combination of lenses Here, \(f_{1}=\) focal length of equiconvex lenses of glass. \(f_{2}=\) focal length of lens formed by water (concave). The focal length of the combination.…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- The displacement of a plane progressive wave in a medium, travelling towards positive \(x\)-axis with velocity \(4 \mathrm{~m} / \mathrm{s}\) at \(t=0\) is given by \(y=3 \sin 2 \pi\left(-\frac{x}{3}\right)\). Then the expression for the displacement at a later time \(t=4\) sec will beWBJEE 2023 Easy
- The period of oscillation of a simple pendulum of length \(l\) suspended from the roof of a vehicle, which moves without friction down an inclined plane of inclination \(\alpha\), is given byWBJEE 2011 Medium
- A particle moves with constant acceleration along a straight line starting from rest. The percentage increase in its displacement during the 4th second compared to that in the 3rd second isWBJEE 2014 Easy
- Four small objects each of mass \(m\) are fixed at the corners of a rectangular wire-frame of negligible mass and of sides \(a\) and \(b(a>b)\) If the wire frame is now roated about an axig passing along the side of length \(b,\) then the moment of inertia of the system for this axis of rotation isWBJEE 2013 Medium
- Half-life of a radioactive substance is 20 minute. The time between \(20 \%\) and \(80 \%\) decay will be :WBJEE 2010 Medium
- A uniform thin rod of length \(L\), mass \(m\) is lying on a smooth horizontal table. A horizontal impulse \(P\) is suddenly applied perpendicular to the rod at one end. The total energy of the rod after the impulse isWBJEE 2021 Medium
More PYQs from WBJEE
- The isomerisation of 1 -butyne to 2 -butyne can be achieved by treatment withWBJEE 2017 Easy
- Let \(f(x)\) denotes the fractional part of a real number \(x\). Then, the value of \(\int_{0}^{\sqrt{3}} f\left(x^{2}\right) d x\) isWBJEE 2015 Medium
- The integrating factor of the differential equation \(\frac{d y}{d x}+\left(3 x^{2} \tan ^{-1} y -x^{3}\right)\left(1+y^{2}\right)=0\) isWBJEE 2015 Medium
- Let \(A=\left[\begin{array}{ccc}5 & 5 \alpha & \alpha \\ 0 & \alpha & 5 \alpha \\ 0 & 0 & 5\end{array}\right]\). If \(|\mathrm{A}|^2=25\), then \(|\alpha|\) equals toWBJEE 2025 Easy
- In a slide caliper, \((m+1)\) number of vernier divisions is equal to \(m\) number of smallest main scale divisions. If \(d\) unit is the magnitude of the smallest main scale division, then the magnitude of the vernicr constant isWBJEE 2012 Medium
- The value of \(\left(\frac{1+\sqrt{3} i}{1-\sqrt{3 i}}\right)^{64}+\left(\frac{1-\sqrt{3} i}{1+\sqrt{3} i}\right)^{64}\) isWBJEE 2015 Easy